Method and device for forming horizontal stacks of printed products and securing said stacks with straps

ABSTRACT

Recumbent stacks of printed products are produced and strapped by supplying the printed products from above onto a conveying surface ( 2 ) where they are lined up in an upright position forming a continuously growing stack ( 6 ), separating discreet stacks ( 7 ) from the growing stack, stabilizing the discreet stacks with endplates ( 4 ), and conveying the stabilized stacks to a strapping position ( 12 ), in which a loop of strapping material is tightened around the stack ( 7 ). For conveying and strapping, the isolated stack ( 7 ) is gripped between two compression jaws ( 10, 11 ) that extend into the stack area ( 16 ) from a first side. In the strapping position ( 12 ), a strapping device ( 30 ) is situated on the side opposite the stack area ( 16 ). For strapping, at least part of the strapping device is moved horizontally in relation to the stack, and transverse to the stacking direction (S), thereby placing a loop of the strapping material around the stack. The loop is then tightened and closed around the stack and the compression jaws ( 10, 11 ) and the strapped stack is separated from the compression jaws by moving the stack ( 7 ) and the compression jaws ( 10, 11 ) relative to each other, horizontally and transverse to the stacking direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is situated in the area of the further processing ofprinted products and concerns a method and device in accordance with thegeneric parts of the corresponding, independent claims. Method anddevice serve the production and strapping of recumbent stacks of printedproducts.

2. Description of the Related Art

In the printing industry, intermediate and part products, such asindividual sections of newspapers and periodicals being printed prior toother sections, signatures to be made into books, or single sheets,prospectuses, small brochures, part sheets, etc. to be inserted intonewspapers or periodicals as supplements or as collated parts, requireintermediate storage between production and further processing andtherefore must be transported within the company or, if necessary, fromone company to another. For such intermediate storage and transportationit has long proven advantageous to arrange the intermediate products inrecumbent stacks, so called bars, and e.g. to store and transport these,stacked on pallets.

Usually the length (perpendicular to the flat surface of the printedproducts) of these aforementioned stacks is substantially greater thanthe length of the edges of the printed products. This means that suchstacks are unstable without aid, even in an upright position. The lengthof the stacks corresponds e.g. with the measurements of the pallets onwhich they are stacked to be stored and transported, i.e. the stacksnormally measure 120 or 150 cm in length and may contain e.g. 200 to 300printed products. The stacks are laid on to the pallets and stacked ontop of each other, forming storage units which are easily and compactlyhandled with commonly used warehouse vehicles.

The ends of the stacks are usually stabilized by endplates, e.g. woodenplates which correspond in size to the stacked products, and the stacksare held together in a compressed condition by a strap, e.g. consistingof a plastic tape. The strap runs across the longer edge of rectangularproducts; depending on the format of the product, once in the middle, ortwice dividing the stack face into three about equal parts.

The recumbent stacks are usually produced by lining up products standingon one edge, by stabilizing the lined-up products at either end withendplates, and by subsequent compression and strapping. The printedproducts to be processed into such stacks are therefore e.g. supplied ina stream of printed products overlapping each other (imbricated stream)from above on to a horizontal, or slightly sloping, conveying surfaceand are positioned thereon. Standing one behind the other on one edge(usually folding edge or back edge) and supporting each other on theconveying surface, they are conveyed or pushed away from the supplypoint. Thus a recumbent stack is formed on the conveying surface whichstack grows continuously in the stacking direction (conveying directionof the conveying surface). From this continuously growing stack,discreet stacks of a pre-determined length or number of products aresuccessively isolated, fitted with endplates on both ends, compressedand strapped. The endplates are usually positioned during stack growthin corresponding gaps of the growing stack. In order to be strapped, theisolated stacks, fitted with endplates, are accelerated in stackingdirection and conveyed into a strapping position. After strapping thestacks are conveyed away.

A device for the formation and strapping of recumbent stacks of printedproducts, as described briefly above, is e.g. known from the publicationU.S. Pat. No. 4,772,003 (Nobuta et al.). In this device an imbricatedstream is supplied from above on to a slightly sloping conveyingsurface. The supply is periodically interrupted such that discreetstacks are produced straight away. In order to support the stacks beingformed on the conveying surface, to position the endplates, and toforward the complete stack in the stacking direction, intermittentlyactivated elements are used; three of which reaching into the area ofthe stack from below the conveying surface and one from above. To becompressed and strapped, the forwarded complete stack is pushedtransverse to the stacking direction into a compression and strappingstation, its faces being supported by stationary supports.

A further device for producing and strapping recumbent stacks of printedproducts is known from the publication EP-0623542 (Grapha-Holding AG).In this device an imbricated stream is continuously supplied on to theconveying surface, creating a continuously growing stack. To interceptthe continuously growing stack a four-part dividing element is insertedinto the stack at the supply point, is conveyed with the growing stackin the stacking direction, and is then straddled to create a gap. Halvesof a downstream and an upstream compression jaw, which also position theendplates, are inserted into the gap from either side of the stack. Thecompression jaws take over the stack from the components of thefour-part dividing element and forward it in stacking direction to becompressed and strapped. The compression jaws are arranged on a guidesystem above the conveying surface, which enables them to move back andforth parallel to the stacking direction. In addition, the halves of thecompression jaws can be moved transverse to the stacking direction inand out of the stack area. A stationary looping channel is provided inthe strapping position. For strapping, strapping material positioned inthe looping channel is extracted to be placed around the stack and isthen tightened. The looping channel comprises two vertical components,one on the entry side and one on the exit side of the strappingposition, and a horizontal component which connects the verticalcomponents by reaching lengthwise across a stack to be strapped. Thehorizontal channel component is arranged in such a way that it liesbetween the two halves of the compression jaws which convey the stackinto the strapping position. For this conveyance the entry side verticalchannel component is lowered below the conveying surface. This meansthat the loop of the strapping material cannot be placed in the loopingchannel until the stack is positioned in the strapping position and thevertical channel component has been repositioned in its active positionabove the conveying surface.

SUMMARY OF THE INVENTION

The invention includes a method and a device for producing and strappingrecumbent stacks, wherein the method and device according to theinvention are to be simpler and more flexible than corresponding methodsand devices according to the state of the art, and are to allow shortertime cycles, in particular for the strapping.

This is accomplished by the method and device as defined by the claims.

According to the invention an advantageously pre-formed loop ofstrapping material (or a looping channel in which the loop is formedrespectively) is placed around the recumbent stack being compressed andbeing positioned in the strapping position by two compression jaws.Positioning of the loop is carried out by a corresponding relativemovement between loop and stack (with compression jaws), the movementbeing substantially horizontally and transverse to the stackingdirection. Advantageously the loop, or looping channel, is moved towardsthe positioned stack. In order to make this corresponding motionpracticable with simple means, the compression jaws are equipped forholding the stack from the one side of the conveying surface which isopposite the side from which the loop is positioned and, if necessary,it is equipped for being strapped together with the stack. This kind ofstrapping necessitates a further, essentially horizontal motiontransverse to the stacking direction for separating the compression jawsfrom the stack after strapping. This movement which is a relativemovement between the strapped stack and the compression jaws isadvantageously a movement of the compression jaws away from theircompressing position on the stack into an inactive position beside thestack.

In the preferred embodiment of the invention a discreet stack isisolated from the continuously growing stack and is further conveyedinto a strapping position between the two compression jaws, whichprotrude into the stack area from one side only. In the strappingposition an advantageously pre-positioned loop is placed around thestack and the compression jaws (movement of loop or looping channel,essentially horizontal and transverse to the stacking direction), andthe stack, if necessary together with the compression jaws, is strappedby tightening and closing the loop. Then the compression jaws areretracted laterally from the stack area and the strapped stack isconveyed away from the strapping position in a suitable manner, e.g.transverse to the stacking direction.

It is obvious that the described strapping procedure offers a very highflexibility concerning the position and number of straps to bepositioned around each stack. A predetermined positioning of the strapon the stack is achieved by proportioning the corresponding motionbetween stack and loop. For positioning a plurality of straps, anappropriately dimensioned intermediate motion is carried out betweensuccessive strappings.

Since the loop of strapping material is able to be made ready prior to,or during, the positioning of the stack in the stacking position, andsince after positioning the stack the loop only needs to be shifted ashort distance (e.g. half the width of the stack), the time required forthe strapping is shorter than it is possible in an device in which thelooping channel is not brought into a functional condition to enable theloop to be made ready until after the positioning of the stack.Therefore, according to the invention more time is available for movingthe stack into the strapping position and therefore, the capacity can beincreased, and/or shorter stacks can be produced.

It shows that the isolation of discreet stacks from the continuouslygrowing stack, the positioning of the endplates at the ends of theisolated stacks, and the taking over of the stacks by the compressionjaws are particularly easily achieved if the compression jaws reach intothe stack area above the conveying surface from one side only. For thispurpose, two support elements are advantageously employed, which can bebrought into the stack area from below (raised, active position) andretracted from the stack area (lowered, inactive position) and can becyclically moved back and forth, parallel to the stacking direction. Thedesign of the support elements is such that they can be simultaneouslypositioned in the same position of the stack area, i.e. one supportelement can be slotted into the other one.

BRIEF DESCRIPTION OF THE DRAWINGS

The method according to the invention and an exemplary embodiment of thedevice according to invention are described in further detail inconnection with the following Figures, wherein:

FIG. 1 is a schematic side view of an exemplary embodiment of the deviceaccording to the invention;

FIG. 2 shows an exemplary embodiment of the two support elements of thedevice according to the invention;

FIG. 3 shows an exemplary embodiment of the two compression jaws of thedevice according to the invention;

FIGS. 4 to 6 show the strapping position of the device according to theinvention viewed in a direction opposing the stacking direction in threephases of the strapping process (moment of conveyance of the stack intothe strapping position: FIG. 4; moment of strapping: FIG. 5; moment ofconveying away of the strapped stack: FIG. 6);

FIG. 7 shows an example of a time/path diagram for the two supportelements and the two compression jaws of the device according to theinvention;

FIGS. 8 to 13 show successive phases of the isolation of a discreetstack from the continuously growing stack.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a side view of an exemplary embodiment of the device accordingto the invention. The device comprises in a generally known manner asupply means 1 and a conveying surface 2, as well as a means 3 forpositioning the endplates 4. The supply means 1 comprises e.g. a pair ofconveyor belts, driven counter-revolvingly, between which an imbricatedstream 5 is conveyed from above on to the conveying surface 2 (supplypoint Z). The conveying surface 2 is e.g. a conveyor belt moving awayfrom the supply point (stacking direction S) or a plurality of conveyorbelts operating in parallel and/or in series. It is advantageous toprovide a first conveyor belt 2.1 adjacent the supply point Z, whichfirst conveyor belt is operated continuously with approximately thespeed of the stack growth and a second conveyor belt 2.2 which isoperated with a cyclically variable speed.

The supplied products line up on the conveying surface 2 to form acontinuously growing stack 6, which expands in the stacking directiondue to the supply of further products and due to the conveying effect ofthe conveying surface 2 (speed of stack growth). From the continuouslygrowing stack 6 discreet stacks 7 are isolated and conveyed between anupstream compression jaw 10 and a downstream compression jaw 11 into thestrapping position 12, advantageously being compressed during thisconveyance and strapped in the strapping position 12. The compressionjaws 10 and 11, which move back and forth in parallel to the stackingdirection, are e.g. arranged on a compression carriage 13 (see also FIG.3), which moves back and forth parallel to the stacking direction andwhich is arranged beside the stack area. In order to isolate thediscreet stacks 7 and to transfer them to the compression jaws 10 and11, a first support element 14 and a second support element 15 areemployed, wherein the support elements have an active position above theconveying surface and an inactive position below the conveying surface,and are designed in such a way that the second support element 15 can beinserted into the growing stack 6 at a point where the first supportelement 14 is already positioned (see also FIG. 2).

The means 3 for positioning the endplates 4 at both ends of the stack tobe isolated, or already isolated, is situated above the stack area 16and advantageously comprises a plate magazine whose front is equipped toposition endplates 4 in the stack area and to move, if necessary, anendplate to be positioned in stacking direction S (see also FIGS. 8 to13).

Situated near the strapping position 12 is a strapping device 30 (seealso FIGS. 4 to 6), of which FIG. 1 only shows the looping channel 31comprising a closing means 31′. Together with the closing means 31′ thelooping channel 31 forms a substantially closed loop, the format ofwhich is adjusted to the format of the isolated stack 7. The closingmeans 31′ is equipped for guiding the strapping material into thelooping channel 31, for gripping the free end of the strapping materialloop in the looping channel, for retracting the strapping material totighten it around the stack, as well as for closing the strapping andfor severing the strapping from the further supply of strappingmaterial.

The expression ‘stack area’ is used in the present description for theroom needed by the growing stack 6 and by the isolated stacks 7 untilthey are strapped. This room extends above the conveying surface 2 fromthe supply point Z to the strapping position 12, and is as high and aswide as the largest printed products to be processed by the device. Thestack area is indicated in the Figs. by dash dot lines and is designatedwith the numeral 16.

FIG. 2 shows an exemplary embodiment of the two support elements 14 and15 of the device according to the invention. The first support element14 is shown in its active position (at least partially protruding abovethe conveying surface). In this position it serves to divide thesupplied imbricated stream at the supply point and subsequently itserves to support the downstream end of the continuously growing stack,for which purpose it is moved in stacking direction S. For returning toits original position it is lowered beneath the conveying surface. Thesecond support element 15, which serves to isolate a discreet stack, totemporarily support the trailing end of the isolated stack, and totemporarily support the downstream end of the continuously growingstack, is shown in its inactive position (lowered beneath the conveyingsurface) at the same distance downstream from the supply point as thefirst support element 14.

For enabling the second support element 15 to be raised from itsinactive position into its active position above the conveying surface,it consists e.g. of two support pieces 15.1 distanced from one another.These support pieces are designed for being inserted betweencorrespondingly spaced support pieces 14.1 of the support element 14.The arrow illustrates the insertion of the second support element 15into the first support element 14.

The function of the two support elements 14 and 15 is described indetail in connection with FIGS. 7 to 13.

FIG. 3 shows, viewed from above, an exemplary arrangement of theupstream and downstream compression jaws 10 and 11 for the deviceaccording to the invention. The compression jaws 10 and 11 are arrangedon the compression carriage 13 which is displaceable parallel to thestacking direction S alongside the stack area, wherein the twocompression jaws 10 and 11 are in addition movable independent of eachother, back and forth on the compression carriage, again parallel to thestacking direction S. The two compression jaws 10 and 11 are shown in acompressing configuration (uninterrupted lines), i.e. inserted in thestack area 16 (active position) and gripping between them an isolatedstack 7 with endplates 4, ready to be strapped. Both compression jaws 10and 11 are also illustrated in their starting position (dash dot lines,10′ and 11′).

The upstream compression jaw 10 is moved on the compression carriagefrom position 10′ to position 10. This movement serves to compress astack 7 positioned between the compression jaws. For effecting thismovement guides 40 and e.g. an actuator 41 are provided. The downstreamcompression jaw 11 is moved from position 11′ into position 11, whereinit supports the downstream end of the continuously growing stack. Themovement of the compression carriage serves to convey the isolated stack7 into the strapping position, wherein the stack is compressedimmediately before or during the conveyance. The compression carriage 13and the downstream compression jaw 11 are driven by the actuator 43.

FIGS. 4 to 6 illustrate the strapping of a separated stack 7 in thestrapping position (viewing direction opposing the stacking direction).

FIG. 4 illustrates the stack 7, being gripped between the twocompression jaws 10 and 11 (downstream compression jaw visible only),and being conveyed into the strapping position or being positioned inthe strapping position. The compression jaws are in their activeconfiguration (protruding from one side into the stack area). Thestrapping device 30 is situated on the other side of the stack area. Themain components of the strapping device are the looping channel 31(closing means not visible), a supply coil 32 of strapping material, anda stack support 33 (e.g. a roller track) being arranged perpendicular tothe stacking direction and possibly being powered.

At least the looping channel 31 with the closing means or advantageouslythe entire strapping device 30 being designed as an independent module,is movable transverse to the stacking direction into at least twodifferent positions. FIG. 4 illustrates the strapping device in itsinactive position, in which the looping channel 31 is positioned on theone side of the stack area, which is opposite to the stack area sidefrom which the compression jaws 10 and 11 protrude into the stack area.

FIG. 5 illustrates the strapping device 30 in its active position, inwhich the looping channel 31 runs lengthwise around the stack 7positioned in the strapping position, e.g., as illustrated, around themiddle of the stack 7. As soon as the strapping device has reached thisposition the strapping operation is activated, wherein e.g. asillustrated the compression jaws 10 and 11 are strapped together withthe stack. In the case of shorter compression jaws, and/or if thestrapping was to be placed further left, the compression jaws would notbe strapped.

FIG. 6 illustrates the strapped stack 7, separated from the compressionjaws by retrieving the compression jaws into their inactiveconfiguration. The stack is now being conveyed away in a directiontransverse to the stacking direction. The strapping device 30 hasreturned to its inactive position.

From FIGS. 4 to 6 it is clear that, instead of the strapping device 30moving back and forth from an inactive position (FIGS. 4 and 6) into anactive position (FIG. 5), the compression jaws 10 and 11 could also bedesigned for being extended into further positions while the strappingdevice 30, or rather the looping channel 31, remains stationary. Toseparate the strapped stack 7 from the compression jaws 10 and 11, asillustrated, the compression jaws are advantageously retracted intotheir inactive configuration, wherein the weight of the stack is usuallysufficient to keep the stack from being moved together with the stack.Stack separation can also be implemented by shifting the stack 7transverse to the stacking direction against the strapping device 30. Inthis case action of the stack support 33 may not suffice for effectingthe separation, so that further suitable means to shift the stack are tobe provided.

FIGS. 7 to 13 illustrate schematically the function of those elements ofthe device according to the invention, which serve to isolate a stack 7from the continuously growing stack 6 and to temporarily support thefree stack ends. These elements are in particular the two supportelements 14 and 15, and the two compression jaws 10 and 11. FIG. 7 is atime/path-diagram, wherein the time axis is directed from top to bottomand the stacking direction S from left to right. FIGS. 8 to 13 show in aside view (essentially as in FIG. 1), successive phases of the stackformation. FIG. 7 and FIGS. 8 to 13 show about the same process butdiffer in some details which illustrate the fact that there are variousembodiments of the method according to the invention. All the same, themoments indicated along the time axis in FIG. 7 correspond in the mainwith the moments shown in FIGS. 8 to 13. In FIG. 7, drawn-out linessignify elements in their active configuration, intermittent linessignify elements in their inactive configuration. In FIGS. 8 to 13 onlythe most important reference numerals are provided. Further referencenumerals mentioned in the text can be seen in FIG. 1.

The two support elements 14 and 15 and the two compression jaws 10 and11 alternately conduct (in their active configuration) an active forwardstroke in stacking direction S from an upstream starting position (14A,15A, 10A, 11A) to a downstream end position (14B, 15B, 10B, 11B) and (intheir inactive or possibly active configuration) a passive return strokein the reverse direction.

The first support element 14 serves to divide the growing stack 6 and totemporarily support its downstream end. Its starting position 14A lies,upstream of the supply point Z. The speed of its active forward strokeis, in the main, the same as the speed of the stack growth.

The second support element 15 serves together with the first supportelement 14 to divide the growing stack 6 and to temporarily support theupstream end of an isolated stack 7 and to transfer this stack end tothe upstream compression jaw 10. It further serves to temporarilysupport the downstream end of the growing stack 6 and to transfer thisstack end to the downstream compression jaw 11. Its starting position15A lies downstream of the supply point Z and upstream of the endposition 14B of the first support element 14. The end position 15B ofthe second support element 15 lies downstream of the end position 14B ofthe first support element 14 and downstream of the starting position 10Aof the upstream compression jaw 10. The forward stroke of the secondsupport element 15 is interrupted by a passive phase, in which theelement is stationary (FIG. 7 with only one position E of the endplatesupply) or moves upstream (FIGS. 8 to 13 with two positions E1 and E2 ofthe endplate supply). Before the passive phase the speed of the secondsupport element 15 is greater than the speed of the stack growth, afterthe passive phase it is about the same as the speed of stack growth.

The upstream compression jaw 10 serves the compression of the completestack and its conveyance into the strapping position. Its starting point10A lies upstream of the position that the second support element 15reaches in the first part of its forward stroke, its end position 10Blies on the entry side of the strapping position 12. Its forward speedis considerably greater than the speed of the stack growth.

The downstream compression jaw 11 serves the temporary support of thedownstream end of the growing stack and the conveyance of the isolatedstack into the strapping position 12. Its starting position 11A liesdownstream of the starting position 10A of the upstream compression jaw10 and downstream of the end position 15B of the second support element15. Its speed is in the first phase of its forward stroke about the sameas the speed of the stack growth, then considerably greater.

The functional cycles of the two support elements 14 and 15 and of thetwo compression jaws 10 and 11 are inter-engaging and proceed asfollows:

While the downstream compression jaw 11 supports the downstream end ofthe growing stack 6, the first support element 14 is moved from itsstarting position 14A (FIG. 8) through the supply point Z into thecontinuously growing stack and past the starting position 15A of thesecond support element 15 to its end position 14B. At the startingposition 15A of the second support element 15 the latter is insertedfrom below into the first support element 14 (FIG. 9) and is thenaccelerated relative to the first support element such that between thetwo support elements a gap is formed in the growing stack 6. Thereby thesecond support element 15 supports the upstream end of an isolated stack7 and the first support element 14 supports the downstream end of thecontinuously growing stack 6.

While the first support element 14 is moved at the speed of the stackgrowth, the second support element 15 pushes the upstream end of theisolated stack 7 just downstream of the starting position 10A of theupstream compression jaw 10, which is then inserted into the stack area.Between the upstream compression jaw 10 and the second support element15 (endplate positioning E or E1) the rear endplate 4 is then positioned(FIG. 10), whereupon the second support element 15 is lowered beneaththe conveying surface. The upstream compression jaw 10, which has takenover the upstream end of the isolated stack, now starts its forwardstroke, which comprises a compression stroke (motion of the upstreamcompression jaw on the compression carriage) and a conveying stroke(travel of the compression carriage) (FIG. 11, after the compressionstroke). The compressed stack is now positioned between the twocompression jaws 10 and 11 and can be conveyed into the strappingposition (forward travel of the compression carriage).

The lowered second support element 15 waits for the first supportelement 14 (embodiment according to FIG. 7) or moves towards the firstsupport element 14 (embodiment according to FIGS. 8 to 13) until the twosupport elements are close enough to each other for enabling the frontendplate 4 to be positioned (endplate positioning E or E2) there between(FIG. 12). The first support element 14 has thereby reached its endposition 14B and is lowered beneath the conveying surface. The secondsupport element 15 begins the second part of its forward stroke, whereinit is brought almost to the starting position 11A of the downstreamcompression jaw 11 (FIG. 13). The second support element 15 is loweredunderneath the conveying surface and begins its backward stroke, whilethe front compression jaw 11, supporting the downstream end of thegrowing stack, begins the first part of its forward stroke at the speedof the stack growth (motion of the downstream compression jaw 11 on thecompression carriage).

Throughout the entire operation, the first conveyer belt 2.1 is drivenat a speed roughly equivalent to that of the stack growth. During thefirst part of the forward stroke of the downstream compression jaw 11,the second conveyer belt 2.2 is driven at the same speed as the firstconveyer belt, during the second part of the forward stroke of thedownstream compression jaw 11 (forward travel of the compressioncarriage), at roughly the same speed as the compression carriage 13.

The advantages of method and device according to the invention lie inthe simplicity of the means, which serve for isolating the discreetstacks from the continuously growing stack, for positioning theendplates, for conveying the discreet stack into the strapping positionand for strapping the stacks; as well as in the simplicity with whichthese means are controlled. Further advantages lie in the form andcontrol of the compression jaws and in the relative motion between thestack to be strapped and the strapping device. These two characteristicspermit compressing the stack and placing a loop of strapping material inthe looping channel, during conveyance of the stack into the strappingposition, and therefore, they allow a very short cycle time.Furthermore, the strapping of stack and compression jaws, combined withthe aforementioned relative motion, permits an extremely simple switchfrom a single to a multiple, e.g. double, strapping.

1. A method producing and strapping recumbent stacks of printedproducts, comprising the steps of: supplying the printed products at asupply point (Z) from above on to a conveying surface (2); conveying theprinted products, which are standing on one edge, on the conveyingsurface as a continuously growing stack in a stacking direction (S) awayfrom the supply point (Z); isolating discreet stacks (7) from thecontinuously growing stack; positioning endplates (4) at a downstreamand an upstream end of each discreet stack; and conveying each isolateddiscreet stack while holding said each isolated discreet stack between adownstream and an upstream compression jaw (11 and 10), in the stackingdirection (S) into a strapping position (12); compressing each isolateddiscreet stack and, while compressed, strapping same with a strappingmaterial, and wherein, in order to convey the discreet stack (7) intothe strapping position (12), moving the two compression jaws (10,11)into the stack area from a first side of the conveying surface (2) in anessentially horizontal motion transverse to the stacking direction (S),and wherein, for strapping, preparing a loop of strapping material on asecond side of the conveying surface (2) opposite its first side andpositioning the loop around the stack (7) through an essentiallyhorizontal relative motion transverse to the stacking direction, betweenthe loop and the stack (7) held by the compression jaws (10,11).
 2. Themethod according to claim 1, wherein, by tightening the loop, the stack(7) is strapped together with the compression jaws (10, 11) and thestrapped stack (7) is separated from the compression jaws (10, 11) by anessentially horizontal relative motion transverse to the stackingdirection, between the compression jaws (10, 11) and the strapped stack(7).
 3. The method according to claim 1, wherein the stack (7), heldbetween the compression jaws (10, 11), remains stationary in thestrapping position (12) and the loop is moved towards the stack (7). 4.The method according to claim 2, wherein, in order to separate the stack(7) from the compression jaws (10, 11), the compression jaws areretracted from the stack area (16).
 5. The method according to claim 1,wherein, between successive strapping processes, a further essentiallyhorizontal relative motion transverse to the stacking direction, isperformed between the loop and the stack (7) held by the compressionjaws (10, 11).
 6. The method according to claim 1, wherein, in order toisolate the discreet stack (7) from the continuously growing stack (6),comprising the further steps of: moving a first support element (14) instacking direction (S) from a starting position (14A) upstream of thesupply point (Z) through the supply point (Z); inserting a secondsupport element (15) from below the conveying surface (2) into the firstsupport element (14) in a position downstream of the supply point (Z)and, in relation to the first support element (14), the second supportelement (15) is accelerated in stacking direction (S).
 7. The methodaccording to claim 6, wherein, in order to transfer the upstream end ofan isolated stack (7) to the upstream compression jaw (10), the secondsupport element (15) is moved in stacking direction (S) just downstreamof a starting position (10A) of the upstream compression jaw (10), theupstream compression jaw (10) is moved into the stack area (16) and isthen moved in stacking direction (S), and the second support element(15) is lowered below the conveying surface (2).
 8. The method accordingto claim 7, wherein the rear endplate is positioned between the upstreamcompression jaw (10) and the second support element (15) before thesecond support element (15) is lowered.
 9. The method according to claim7, wherein, in order to transfer the downstream end of the continuouslygrowing stack (6) to the downstream compression jaw (11), comprising thefurther steps of: the second support element (15) waiting downstream ofthe starting position (10A) of the upstream compression jaw (10), movingthe upstream compression jaw (10) into the stack area (16) and is thenin stacking direction (S), and lowering the second support element (15)below the conveying surface (2).
 10. The method according to claim 9,wherein the front endplate (4) is positioned between the first supportelement (14) and the second support element (15) before the firstsupport element (14) is lowered.
 11. The method according to claim 8,wherein the endplates (4) are inserted into the stack area from abovefor being positioned at the stack ends.
 12. A device for producing andstrapping recumbent stacks of printed products, said device comprising asupply point (Z) where the printed products are supplied from above onto a conveying surface (2), wherein the conveying surface extends fromthe supply point (Z) in stacking direction (S) to a strapping position(12) and a stack area (16) is reserved above the conveying surface, andsaid device further comprising means for isolating discreet stacks (7)from a stack (6) that is continuously growing along the conveyingsurface (2), means for position endplates (4) at a downstream and anupstream end of the isolated stack (7), an upstream and a downstreamcompression jaw (10, 11) for holding the isolated stack and forconveying the held stack into the strapping position (12), and astrapping device (30) for strapping the isolated stack (7) in thestrapping position, wherein the compression jaws (10, 11) are arrangedto be moveable from a first side of the stack area (16) into and out ofthe stack area (16), the strapping device (30) comprises a loopingchannel (31) with a closing means (31′), the strapping device beingarranged in the area of the strapping position, at least when inactive,on a second side of the stack area (16) opposite the first side, and thecompression jaws (10, 11) and the looping channel (31) with the closingmeans (31′) are moveable relative to each other, substantiallyhorizontally and transverse to the stacking direction (S).
 13. Thedevice according to claim 12, wherein the compression jaws (10, 11) whenpositioned in the stack area (16) reach from the first side of the stackarea (16) beyond the middle of the stack area (16).
 14. The deviceaccording to claim 12, wherein the conveying surface (2) comprises aconveyor belt (2.1) that is adapted to be driven at a constant speed,away from the supply point (Z), as well as a second conveyor belt (2.2)that is adapted to be driven at a variable speed and being arrangedadjacent the first conveyor belt (2.1).
 15. The device according toclaim 12, further comprising a compression carriage (13) that is adaptedto move back and forth in parallel to the stacking direction (S), saidcompression jaws (10, 11) being arranged on the compression carriage(13), said compression jaws being moveable independently of each otherback and forth parallel to the stacking direction (S).
 16. The deviceaccording to claim 12, wherein the means for isolating a discreet stack(7) comprises a first support element (14) and a second support element(15), both support elements (14, 15) being are designed to be moveableback and forth parallel to the stacking direction (S) and to be loweredand raised below and above the conveying surface (2) and to bepositioned simultaneously in the same spot of the stack area (16). 17.The device according to claim 12, wherein the means for positioning theendplates (4) comprises an endplate storage unit (20) situated above thestack area (16), a head (21) of said endplate storage unit being isequipped for positioning endplates (4) in the stack area (16).
 18. Thedevice according to claim 17, wherein, in addition to being equipped forpositioning endplates, the head (21) is further equipped for moving theendplates parallel to the stacking direction (S).